1. Field of the Invention
The present invention relates generally to medical apparatus and, more particularly, to methods and apparatus for cutting and removing soft tissue by aspiration.
2. Description of Related Art
Turning to FIG. 1, a prior art optical cutter includes a fiber guide tube 5, a water line 7, an air line 9, and an air knife line 11 for supplying pressurized air. A cap 15 fits onto the hand-held apparatus 13 and is secured via threads 17. The fiber guide tube 5 abuts within a cylindrical metal piece 19. Another cylindrical metal piece 21 is a part of the cap 15. The pressurized air from the air knife line 11 surrounds and cools the laser as the laser bridges the gap between the two metal cylindrical objects 19 and 21. Air from the air knife line 11 flows out of the two exhausts 25 and 27 after cooling the interface between elements 19 and 21.
The laser energy exits from the fiber guide tube 23 and is applied to a target surface of the patient. Water from the water line 7 and pressurized air from the air line 9 are forced into the mixing chamber 29. The air and water mixture is very turbulent in the mixing chamber 29, and exits this chamber through a mesh screen with small holes 31. The air and water mixture travels along the outside of the fiber guide tube 23, and then leaves the tube and contacts the area of surgery.
Other prior art devices include optical cutting systems utilizing the expansion of water to destroy and remove tooth material, such as disclosed in U.S. Pat. No. 5,199,870 to Steiner et al. This prior art approach requires a film of liquid having a thickness of between 10 and 200 .mu.m. U.S. Pat. No. 5,267,856 to Wolbarsht et al. discloses a cutting apparatus that requires water to be inserted into pores of a material and then irradiated with laser energy. In both patents the precision and accuracy of the cut is highly dependent upon the precision and accuracy of the water film on the material or the water within the pores.
Devices have existed in the prior art for utilizing laser energy to perform liposuction and body contouring procedures, wherein laser energy facilites the separating of soft tissue from a patient in vivo. U.S. Pat. No. 4,985,027 to Dressel discloses a tissue remover that utilizes laser energy from a Nd:YAG to separate tissue held within a cannula, the contents of which are expressly incorporated herein by reference. Use of the Nd:YAG laser for in vivo tissue removal is in some ways inefficient, since the energy from the Nd:YAG laser is not highly absorbed by water. Further, the Nd:YAG laser and other lasers, such as an Er:YAG laser, use thermal heating as the cutting mechanism. Adjacent tissue can be charred or thermally damaged and, further, noxious and potentially toxic smoke can be generated during the thermal cutting operations performed by these prior-art devices.